Update doc comment for std::rt

Author: aturon

src/libstd/rt/mod.rs

@@ -8,38 +8,13 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-//! Runtime services, including the task scheduler and I/O dispatcher
+//! Runtime services
 //!
-//! The `rt` module provides the private runtime infrastructure necessary to support core language
-//! features like the exchange and local heap, logging, local data and unwinding. It also
-//! implements the default task scheduler and task model. Initialization routines are provided for
-//! setting up runtime resources in common configurations, including that used by `rustc` when
-//! generating executables.
-//!
-//! It is intended that the features provided by `rt` can be factored in a way such that the core
-//! library can be built with different 'profiles' for different use cases, e.g. excluding the task
-//! scheduler. A number of runtime features though are critical to the functioning of the language
-//! and an implementation must be provided regardless of the execution environment.
-//!
-//! Of foremost importance is the global exchange heap, in the module `heap`. Very little practical
-//! Rust code can be written without access to the global heap. Unlike most of `rt` the global heap
-//! is truly a global resource and generally operates independently of the rest of the runtime.
-//!
-//! All other runtime features are task-local, including the local heap, local storage, logging and
-//! the stack unwinder.
-//!
-//! The relationship between `rt` and the rest of the core library is not entirely clear yet and
-//! some modules will be moving into or out of `rt` as development proceeds.
-//!
-//! Several modules in `core` are clients of `rt`:
-//!
-//! * `std::task` - The user-facing interface to the Rust task model.
-//! * `std::local_data` - The interface to local data.
-//! * `std::unstable::lang` - Miscellaneous lang items, some of which rely on `std::rt`.
-//! * `std::cleanup` - Local heap destruction.
-//! * `std::io` - In the future `std::io` will use an `rt` implementation.
-//! * `std::logging`
-//! * `std::comm`
+//! The `rt` module provides a narrow set of runtime services,
+//! including the global heap (exported in `heap`) and unwinding and
+//! backtrace support. The APIs in this module are highly unstable,
+//! and should be considered as private implementation details for the
+//! time being.
 
 #![experimental]